This invention relates to monitoring the orientation of an object and particularly but not exclusively to an object that is capable of moving in a large volume, such as a pilot's helmet.
In the past, monitoring of the orientation of an object has been carried out by electromechancial sensors such as potentiometers or shaft angle encoders attached to the object. For such devices to be used, it is necessary to attach part of the sensor to the object to move with it and another part to some reference point which is stationary relative to the moving object. This arrangement however limits the movement of the object and cannot be used in some applications where total freedom of movement is required, for example, when monitoring the orientation of a pilot's helmet. Such electromechanical devices are also prone to failure, due to wear.